- !! clean up util.ByteStreamBuffers !!
  - orthogonality - m_to_n
    - bytes
    - bytearray
    - memoryview
    - ByteStreamBufferLike
    - ByteStreamBufferView
    - ByteStreamBuffer
  - 'any'?
  - 'can_bytes'?
- hand optimize lol
  - segmented find/rfind are still insane
  - segmented split_to should mutate list in place
- `import bisect` find/rfind initial segment index, `key=len`
- cext lol
